$arr= [
	[1,2,3,4,5,6,7,8,9 ], #works as expected
	[1,2,3,'',5,6,7,'',9 ], #works as expected
	[1,2,3, ,5,6,7, ,9 ],   #does not work as expected "empty fields " are ignored
];

my $dd=Data::Dumper->new([$arr],[ qw(arr) ] )->Indent(1)->Quotekeys(0)->Dump;
print $dd;
$arr = [
  [
    1,
    2,
    3,
    4,
    5,
    6,
    7,
    8,
    9
  ],
  [
    1,
    2,
    3,
    '',
    5,
    6,
    7,
    '',
    9
  ],
  [
    1,
    2,
    3,
    5,
    6,
    7,
    9
  ]
];